The present invention relates to a removable mullion assembly for a double door. More particularly, the present invention relates to a mullion assembly having an engagable latch controlled by a key cylinder lock mechanism.
Mullions are vertically oriented doorway inserts that allow use of single doors in double door frames. Conventionally, mullions are centered in a double doorway and attached with screws or bolts to fittings inset into the floor and the top of the door frame. Two strikes are provided on opposing sides of the mullion to accommodate latches of two single size doors that are respectively hinge mounted on opposite side of the door frame.
When unobstructed access through the double door is needed, conventional mullions must be unscrewed or unbolted from the inset fittings. This can be a time consuming and difficult procedure, and normally requires two people. One person must hold the mullion while the other person unscrews or unbolts the mullion from the fittings. However, repeated removal and replacement of the mullion can also cause problems, with the fittings tending to become loose with time, or screw threads being stripped or damaged.
To overcome this problem, removable mullions that do not require unscrewing or unbolting have been disclosed. For example, U.S. Pat. No. 2,275,730 discloses a mullion capable of being seated in a floor bracket and swung forward to permit a latch bolt to snap into abutting relation with a tooth, holding the mullion in position against a top bracket. The mullion can be released by an actuating chain that retracts the latch bolt into a housing beneath the tooth, permitting inward tilting and removal of the mullion. However, this type of arrangement is disadvantageous for many applications because the mullion release system is not protected, being subject to damage or unauthorized removal by vandals. What is needed is an easily removable mullion assembly that can be snapped into position, has a concealed latch bolt protected from damage, and is not removable by unauthorized persons.
The present invention uses a key controlled mechanism to provide such a vandal resistant mullion assembly. A mullion assembly in accordance with the present invention includes a bottom fitting attached to a floor and a top fitting attached to the door frame above the bottom fitting. In preferred embodiments, the bottom fitting includes protrusions configured to fit within the mullion cavity and hold the mullion in position, although other attachment mechanisms such as bolts, hinges, exterior stops, or other conventional holding mechanisms can also be employed.
The top fitting supports a latch engagement assembly such as a roller strike that downwardly extends from the top fitting. A mullion, defining a mullion cavity therein, is positioned between the bottom fitting and the top fitting, and a latch assembly is positioned in the mullion cavity. The latch assembly includes a platform supporting a latch that automatically extends from the mullion cavity in response to depression of an auxiliary bolt attached adjacent to the latch to engage the latch engagement assembly of the top fitting and hold the mullion in a fixed position.
Importantly, the latch can only be retracted by operation of a key lock assembly connected to the latch assembly by an actuating link assembly. This connection permits key controlled disengagement of the latch from the latch engagement assembly, followed by temporary removal of the mullion from its upright position in the door frame. In preferred embodiments, the key lock assembly includes a mortise key cylinder having a cylinder cam configured to downwardly move the actuating link assembly and retract the latch in response to turning a key in the mortise key cylinder.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.